Vermillion, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

598
FXUS63 KFSD 101655
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1155 AM CDT Tue Jun 10 2025

.KEY MESSAGES...

- Morning showers Wednesday give way to increased risks for
  thunderstorms south of I-90 Wednesday afternoon and evening.
  Marginal (Level 1 of 5) risk for severe weather with large
  hail and isolated strong wind gusts.

- Unsettled pattern with periodic thunderstorm chances continues
  into the weekend. Only marginal confidence on exact timing and
  location, but isolated strong to severe storms and locally heavy
  rain are possible Thursday afternoon/night.

- Temperatures rise through the upcoming weekend, bringing
  additional thunderstorm risks early next week. Monitor for
  strong storm potential Sunday-Monday.

&&

.DISCUSSION...
Issued at 430 AM CDT Tue Jun 10 2025

TODAY-WEDNESDAY MORNING: Building mid-upper level heights today
will allow warmer air to expand into the region, with highs this
afternoon in the mid 80s to mid 90s. Tonight a weak wave will
slide atop the broad upper ridge, dragging a frontal boundary
slowly southeast through the area. This boundary will become a
focus for high-based showers and perhaps a few storms as we
head through tonight and Wednesday morning.

WEDNESDAY AFTERNOON-FRIDAY: The boundary continues to push south
through Wednesday afternoon and should be a focus for late day
thunderstorm development Wednesday. Unfortunately, still not
seeing a lot of agreement on the placement of the surface front,
though broad consensus looks to be between Highway 18 and 20 in
northwest Iowa. As a broad wave arrives from the west, expect to
see storms develop along to just north of the surface boundary in
the late afternoon, tracking east through the evening. Forecast
soundings show the antecedent air mass is still relatively dry in
the mid levels, which could support corridors of stronger winds
with cold-pool dominant storms. Isolated large hail is also
possible, but displacement of the stronger instability south and
stronger shear north of the boundary leaves a narrow corridor of
support for organized hail-producing storms, perhaps as large as
half dollars with the strongest storm cores.

Later Wednesday night into Thursday evening could be a repeat of
tonight. This would begin with development along the elevated
warm front as it lifts back to the north and a weak low level jet
impinges on the boundary into Thursday morning, followed by a
potential for stronger convection Thursday afternoon/evening as
another wave slides into the area. Models begin to show less and
less agreement on placement of boundaries, which will ultimately
depend on the previous day`s activity. This leads to waning
confidence as we move forward in time. However, if there are
boundaries in the area later Thursday, they should become the
focus for late day development. Similar to Wednesday, stronger
instability and shear are not coincident, so again would expect
isolated strong to severe storms.

One additional concern for later Thursday and especially Thursday
night would be a potential for areas of heavy rainfall. Deepening
moisture profiles and warm cloud depths will lead to efficient
rainfall producing storms, and the main question will be whether
successive rounds of showers and storms Wednesday into Thursday
night will impact the same locations or be more transient.

SATURDAY-MONDAY: Not a lot in the fine detail department to latch
onto in this long range period. There is some model consensus
that a broad upper ridge will become established from the Desert
Southwest into the southern-central Plains early next week, and
various shortwaves topping the ridge will bring periodic storm
chances to the northern Plains. However, uncertainty in timing
and location abounds given lack of model agreement in those finer
details. That said, Sunday-Monday will be a period to monitor for
severe weather risks if the storm track falls across our forecast
area.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1153 AM CDT Tue Jun 10 2025

VFR conditions with light elevated smoke layer continue into the
evening hours. A broken mid-lvl cloud deck will form over the
northern half of South Dakota later this evening and overnight,
with widely scattered showers moving along Highway 14 into early
Wednesday. The passage of a weak cold front will bring easterly
winds to most of the CWA north of Highway 20 by mid-morning
Wednesday.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...JH
AVIATION...Dux